Polybutylene terephthalate resin composition and molded article thereof

Abstract

The present invention provides a polybutylene terephthalate resin composition having both low warpage and high durability in a cold cycle environment. Specifically, relative to 100 parts by weight of a polybutylene terephthalate resin (A) having 30 meq / kg or less of the amount of terminal carboxyl groups, there are added a carbodiimide compound (B) in an amount of 0.3 to 2 equivalents of the carbodiimide functional group when the amount of carboxyl terminal group in the polybutylene terephthalate resin (A) is set as 1, 20 to 100 parts by weight of a fibrous filler (C), and 15 to 65 parts by weight of a thermoplastic resin (D) of one or more selected from polycarbonate resin and polyethylene terephthalate resin.

Description

TECHNICAL FIELD[0001]The present invention relates to a polybutylene terephthalate resin composition and a molded article thereof which are excellent in low warpage and resistance to heat shock.BACKGROUND ART[0002]Polybutylene terephthalte resins are used as engineering plastics in wide fields including automobile parts, electric and electronic parts, or the like owing to their excellent mechanical properties, electric properties, and other physical and chemical properties, and their good workability. In particular, since their heat resistance and strength can be increased by adding a fibrous filler such as glass fiber thereto, polybutylene terephthalte resins are often used by reinforcing thereof by the fibrous filler.[0003]Particularly in the field of automobiles, polybutylene terephthalate is often used as a material of sensors used for electrical control and housings of ECU. Since such a product requires low warpage, it is often alloyed with a noncrystalline resin, such as polyc...

AI Technical Summary

Benefits of technology

[0008]The present invention has been made to solve the above technical problems, and an object of the present invention is to provide a polybutylene terephthalate resin composition, which has both low warpage and high durability in a cold cycle environment, and to provide a molded article thereof.

[0009]The inventors of the present invention have conducted detail studies to obtain a polybutylene terephthalate resin composition capable of achieving the above object, and have found that a composition which is made up mainly of a polybutylene terephthalate resin having 30 meq / kg or less of terminal carboxyl groups and to which a specific amount of a carbodiimide compound, a fibrous filler and a polycarbonate resin, and / or a polyethylene terephthalate resin are added in combination imparts an extremely high resistance to heat shock and low warpage without significant deterioration in the mechanical properties, thus having completed the present invention.

[0015]The present invention provides a polybutylene terephthalate resin composition having excellent performance of high durability and the like in a cold cycle environment and having excellent low warpage. The polybutylene terephthalate resin composition of the present invention is useful as various molded articles, in particular insert-molded articles.

Problems solved by technology

However, a large amount of an elastomer is required to be blended to achieve sufficient resistance to heat shock and there has been a problem of reduction in the strength.

In particular, as described above, the resistance to heat shock is prone to be reduced in a system where alloyed with a noncrystalline resin, such as polycarbonate, or added with an inorganic filler of a high aspect ratio in flakes or powder to achieve the low warpage, and it has been difficult to have both the resistance to heat shock and the low warpage.

Although JP-A 53-121843 discloses that low warpage are improved by combining a fibrous filler with a plate filler, this material is low in resistance to heat shock.

In addition, although JP-A 4-169214 describes that the adhesion with an inserted metal is improved by blending polycarbonate and a fibrous and / or nonfibrous filler in polybutylene terephthalate, there is no description regarding the resistance to heat shock, and in reality, in such a composition, the resistance to heat shock is insufficient.

Further, although JP-A 8-311312 describes that the morphological stability and the flexural toughness at low temperatures are improved by blending polycarbonate and a core shell polymer in polybutylene terephthalate, there is no description regarding the resistance to heat shock, and in reality, in such a composition, the resistance to heat shock is insufficient.

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